GaN Semiconductor Structure With Seal Ring Crack Isolation
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Solution Overview
Problem
Existing semiconductor structures with GaN-based devices face reliability issues due to cracks propagating from unprotected portions of the GaN layer during 2.5D or 3D IC packaging, leading to reduced integration density and performance.
Innovation Solution
Forming seal rings directly on a silicon substrate surrounding GaN-based devices, while the devices are formed over a protected region, thereby preventing cracks from propagating into the semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If GaN-based devices are integrated in 2.5D or 3D IC packaging, then integration density is improved, but cracks propagate from unprotected portions of the GaN layer causing reliability degradation
Solution Approach 1:
The patent segments the GaN layer into protected and unprotected portions, with the seal ring structure creating a distinct boundary zone that isolates the device region from crack propagation paths in the unpacked GaN layer
Solution Approach 2:
The seal ring acts as an intermediary structure between the unprotected GaN layer and the protected device region, serving as a barrier that prevents crack propagation into the active device area while allowing high integration density
2Reliability
If seal rings are formed to protect GaN-based devices, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the seal ring formation with the existing interconnect structure fabrication process, using the same deposition and patterning steps to create both the interconnect features and the protective seal ring, thereby reducing overall process complexity
Solution Approach 2:
The seal ring structure serves multiple functions: it protects the GaN layer from crack propagation, provides a boundary for device isolation, and integrates with the interconnect structure, thereby reducing the need for additional separate protective structures
Data Source
AI summary
Semiconductor structures and methods are provided. An exemplary semiconductor structure according to the present disclosure includes a semiconductor substrate including a first region and a second region surrounding the first region, a III-V semiconductor layer disposed directly over the first region, a compound semiconductor device formed in and over the III-V semiconductor layer, a first plurality of conductive features disposed over and electrically coupled to a source contact of the compound semiconductor device, and a seal ring disposed directly over the second region and comprising a second plurality of conductive features, a top surface of a topmost conductive feature of the first plurality of conductive features is higher than a top surface of a topmost conductive feature of the second plurality of conductive features.